Neurone

• Neuron


  A specialized cell in the body that transmits information electrochemically
• Types of neurons


  • Sensory neuron
  • Relay neuron
  • Motor neuron
• Sensory neuron


  • Detects information (e.g. pressure or heat) and passes it through the peripheral nervous system to the central nervous system
• Relay neuron


  • Detects information from the sensory neuron and can pass information to the central nervous system for processing, and can also pass information to motor neurons
• Motor neuron


  • Detects information from relay neurons and carries information to the muscle, making it contract or relax
• Reflex arc


  The collection of neurons that allows reflex actions - the body moving quickly in response to possible danger
• Parts of a neuron


  • Dendrites
  • Cell body
  • Axon
• Dendrites


  Extensions of neurons that attach signals sent from other neurons
• Cell body


  Contains the genetic information of the nerve cell and controls the cell's functions
• Axon


  A long extension of the nerve cell that allows it to pass messages on to other nerve cells
• Myelin sheath


  Insulation around the axon that makes the electrical signal or nerve impulse travel faster
• Sense receptors


  Specialized dendrites that detect external stimuli like heat, taste or light
• Motor end plates


  At the end of motor neurons, attaching them to the muscle fibers used to activate muscles
• Synapse


  The structure where a presynaptic neuron converts an electrical signal into a chemical signal that is then detected by a postsynaptic neuron
• Synaptic transmission


  1. Presynaptic neuron releases neurotransmitters

  2. Neurotransmitters detected by receptors on postsynaptic neuron

  3. Neurotransmitters taken back into presynaptic cell by transport proteins
• Neurotransmitters


  Chemical molecules released by neurons that are detected at receptor sites
• Excitatory neurotransmitters


  Make the postsynaptic cell more likely to fire
• Inhibitory neurotransmitters


  Make the postsynaptic cell less likely to fire
• Summation


  The interaction between excitatory and inhibitory processes that determines whether the postsynaptic cell will fire
• Hebb's theory of learning and neural growth


  Repeated use of a neural connection stimulates growth and strengthening of that connection, forming new neural pathways
• Neuroplasticity


  The brain's physical changes in response to experience
• Cell assemblies


  Groups of neurons that fire together when we learn new things
• The more neural pathways are used, the stronger and more efficient they become
• Biological research has observed the physical growth of neurons when electrically stimulated
• Effective learning is a complex problem that can't be fully explained just by the growth of new synaptic connections